1. Field of the Invention
This invention relates generally to the field of lubricant distributor valves and more particularly to lubricant distributor valves which are constructed, adapted and arranged to operate cyclically, that is, to meter and discharge a predetermined quantity of lubricant to each of a number of points of use, such as bearings, in sequence.
2. Description Of The Prior Art
Lubricant distributor valves of the general type to which reference is made in the introductory paragraph have been known for many years. For reasons mainly involving manufacturing and maintenance ease, such valves have ordinarily been constructed of a plurality of separate parts fastened together by bolts to form a unitary valve structure. The use of bolts or similar fastening devices enables the various parts to be separated and removed from one another for ease in cleaning, repairing and, if necessary, replacing the parts.
Leese et al U.S. Pat. No. 3,219,146, for example, discloses a cyclical lubricant distributor valve in which a series of intermediate block units are disposed between an inlet block unit and an end block unit, and a series of through bolts are used to separably fasten the various block units together in fixed assembly.
As is typical of cyclic lubricant distributor valves to which the present invention pertains, the valve disclosed in the Leese et al patent includes at least three intermediate block units, each of which contains a bore and a spool movable back and forth within the bore. The spools of the various intermediate block units move sequentially and as each spool moves it performs two functions.
First, the spool serves to force a predetermined quantity of lubricant through an outlet to a bearing or other point of use. Second, the spool serves as a valve, the operation of which is necessary to the cyclic operation of the entire distributor valve.
In the Leese et al system each of the intermediate block units has a pair of side walls in which a plurality of ports are formed. All of the lubricant which flows from the inlet of the valve to the various outlets flows through the ports formed in the side walls of the intermediate blocks.
Porter et al U.S. Pat. No. 3,298,460 also discloses a cyclic lubricant distributor valve but in that arrangement the valve comprises a single integral base member on which are mounted a plurality of individual block units. The lubricant inlet and the various outlets are formed in the base member. The movable spools are all contained within the individual block units. Each block unit contains a bottom wall in which are formed a number of ports which communicate with corresponding ports formed in the base member. All of the lubricant which flows from the inlet to the various outlets flows through the bottom walls of the individual block units. No fluid communication exists between the side walls of adjacent block units.
It has been suggested that the arrangement disclosed in Porter et al U.S. Pat. No. 3,298,460 enjoys certain advantages over the arrangement disclosed in Leese et al U.S. Pat. No. 3,219,146. See, for example, the article "Divider Valves--A New Design Approach" by Edward B. Porter, Sr. in Iron and Steel Engineer, June, 1967, pages 135 through 142.
While both the Leese et al and Porter et al systems have been advantageously utilized in a variety of applications, neither arrangement, nor any others of which we are aware, would appear to be optimum for all applications.
For example, the Leese et al system can be enlarged in terms of the number of outlets merely by adding additional intermediate block units. In doing so, however, the through bolts must be completely removed. This often requires replacement of all gasketing material, such as O-rings and the like, particularly when the distributor valve is being used in a high pressure application, in which the through bolts must necessarily be highly torqued to avoid leakage between the faying faces of the various block units.
In the Porter et al system the number of block units which are active can be increased (or decreased) without disconnecting the inlet and outlet lines from the base member and without the necessity of removing through bolts which extend through the entire distributor valve. On the other hand, additional outlets cannot be added after the total number for which the base member has been constructed are met. There are, however, a number of applications in which the ultimate number of lubrication points to be serviced by a single distributor valve cannot be predetermined. It is to those applications that the principles of the present invention are particularly concerned.